Solanum aloysiifolium Dunal, Prodr. [A. P. de Candolle] 13 (1): 73. 1852.

3. Solanum aloysiifolium Dunal, Prodr. [A. P. de Candolle] 13(1): 73. 1852. Figs 2B, 12, 13 Solanum filiforme Ruiz & Pav. var. lanceolatum Kuntze, Revis. Gen. Pl. 3(2): 225. 1898. Type. Argentina. Jujuy: sin. loc., P.G. Lorentz & G. Hieronymus 1074 (lectotype, designated by Barboza et al. 2013, pg. 236: NY [00688918]). Solanum lorentzii Bitter, Repert. Spec. Nov. Regni Veg. 11: 2. 1912. Type. Argentina. Achiral, bei San Andres, Sep 1873, P.G. Lorentz & G. Hieronymus 440 (lectotype, designated here: CORD [CORD00004234]; isolectotypes: CORD [CORD00004235], GOET). Solanum oligodontum Bitter, Repert. Spec. Nov. Regni Veg. 11: 215. 1912. Type. Bolivia. Tarija: "Huayavilla, Bolivia australis, apud coloniam", 1903-1904, K. Fiebrig 3428 (holotype: B, destroyed [F neg. 2718], no duplicates found). Solanum bermejense Bitter, Repert. Spec. Nov. Regni Veg. 13: 87. 1913. Type. Bolivia [Argentina]. Bermejo, 17 Nov 1903, K. Fiebrig 2131 (lectotype, designated by Barboza et al. 2013, pg. 236: SI [003294, acc. # 065940]; isolectotypes: GOET [003485], HBG [HBG511408], M [M0171774]). Solanum polytrichostylum Bitter var. lorentzii (Bitter) Edmonds, Kew. Bull. 27: 106. 1972. Type. Based on Solanum lorentzii Bitter. Solanum collectaneum C.V.Morton, Revis. Argentine Sp. Solanum 67. 1976. Type. Argentina. Tucumán: Dpto. Capital, Río Salí, 19 Sep 1920, S. Venturi 919 (holotype: US [00027521, acc. # 1548836]; isotypes: A [00077601], SI [003299, acc. # 162492; 065950, acc. # 065950]). Type. Bolivia. Chuquisaca: "In Boliviae collibus siccis Chuquisaca ", Dec, A. D’Orbigny 1208 (holotype: P [P00319385]; isotype: F [v0073195F]). Description. Shrub to 4 m, woody or subwoody, often with lax sprawling branches, occasionally growing as a small herb. Stems terete, sparsely pubescent with white eglandular 2-3(5)-celled simple uniseriate trichomes to 0.5 mm long, these appressed and usually antrorse; new growth densely pubescent with white eglandular simple uniseriate trichomes like those of the stems, appearing whitish grey in herbarium specimens; bark of older stems pale green-grey. Sympodial units difoliate, the leaves not geminate. Leaves simple, the blades 3-10(19) cm long, 1.5-5(9) cm wide, elliptic to narrowly elliptic, widest at or just below the middle, membranous to chartaceous, concolorous; adaxial surfaces nearly glabrous to sparsely and evenly pubescent with white eglandular simple uniseriate trichomes ca. 0.5 mm long, the pubescence denser on the veins; abaxial surfaces sparsely to moderately pubescent with similar white simple uniseriate trichomes; principal veins 5-6 pairs, more densely pubescent than the lamina; base truncate-attenuate to attenuate, not markedly decurrent onto the stem; margins entire or occasionally irregularly dentate in the basal half; apex acute; petioles 0.3-1 cm long, sparsely to moderately pubescent with white eglandular simple uniseriate trichomes ca. 0.5 mm long like the stems and venation. Inflorescences internodal, forked or occasionally twice-forked, 1.5-4 cm long, with 10-20 flowers borne at the upper half of each branch, moderately to densely pubescent with white eglandular simple uniseriate trichomes to 0.5 mm long, more densely pubescent than the stem; peduncle 0.5-1.8 cm long; pedicels 0.6-0.8 cm long, 0.4-0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, tapering, spreading at anthesis, pubescent with white simple uniseriate trichomes like the rest of the inflorescence, the pubescence sparser than on the inflorescence axis, articulated at the base; pedicel scars irregularly spaced 0.5-1 mm apart, slightly raised from the inflorescence axis. Buds long-ellipsoid, the corolla strongly exserted from the calyx before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 1-1.2 mm long, conical, the lobes 1-1.5 mm long, 1-1.5 mm wide, deltate with an acute tip, sparsely pubescent with white eglandular simple uniseriate trichomes to 0.5 mm long like the pedicels. Corolla 1.2-1.5 cm in diameter, white or occasionally purple-tinged, with a yellowish green central star often with darker margins, stellate, lobed 3/4 of the way to the base, the lobes 4-5 mm long, 1.5-2 mm wide, reflexed at anthesis and spreading with age, glabrous adaxially, sparsely and minutely puberulent and papillate abaxially long the petal midveins tips and margins, the trichomes sparse, to 0.2 mm long, spreading. Stamens equal or occasionally slightly unequal; filament tube minute; free portion of the filaments 0.5-1 mm long, pubescent adaxially with eglandular tangled simple uniseriate trichomes; anthers 4-4.5(5.5) mm long, 0.6-0.7(1) mm wide, narrowly ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary conical, glabrous; style 6.5-8 mm long, straight, exserted beyond the anther cone, densely papillate-pubescent in the lower 2/3 where included in the anther cone; stigma capitate to small-capitate, the surfaces minutely papillate. Fruit a globose berry, 0.4-0.5 cm in diameter, green or purple to greenish purple when ripe, the pericarp thin, matte, opaque, glabrous; fruiting pedicels 1-1.2 cm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, not markedly woody, deflexed to slightly spreading, not persistent; fruiting calyx not accrescent, appressed to the berry, the lobes to 1.5 mm long, occasionally somewhat spreading or reflexed. Seeds 40-60 per berry, 1-1.5 mm long, 0.9-1 mm wide, teardrop shaped, pale tan or yellowish brown, the surfaces minutely pitted, the testal cells shallowly sinuate in outline (nearly rectangular). Stone cells 10 per berry, 4 larger to ca. 1 mm in diameter, 6 smaller ca. 0.5 mm in diameter, all scattered through the berry flesh, cream-coloured. Chromosome number: n = 12 (Moscone 1992, as S. lorentzii and S. lorentzii var. montigenum; vouchers Hunziker et al. 24691, 24711, 24872, 24826, 24833, Subils et al. 3478, 3496, 3497, 3499; Moyetta et al. 2013; voucher Barboza et al. 2210). Distribution (Fig. 14). Solanum aloysiifolium is widely distributed and occurs from central Bolivia to central Argentina. Its southernmost range only just reaches Córdoba Province in central Argentina and it is much more common further north and westward towards the Andes. Ecology and habitat. Solanum aloysiifolium is a weedy species, often growing along roadsides and in open, disturbed areas in a wide variety of habitats, from 100 to 3,000 m elevation. Plants often occur in large patches and can be remarkably morphologically divergent in different habitats. Common names and uses. Argentina. Salta: papa de la vibora (Hilgert & Lamas 1691), sacha ají (Anon. s.n., 7 Jun 1905), yerba mora (Hilgert 2519, 2251). Used medicinally in local communities around Parque Nacional Baritú in montane Salta, Argentina (Hilgert and Gil 2006). Preliminary conservation status (IUCN 2022). Least Concern [LC]. EOO = 1,349,765 km2 [LC]; AOO = 1,596 km2 [VU]. Solanum aloysiifolium is a common and widespread species that occurs in several protected areas in both Bolivia and Argentina. It grows in large stands in disturbed areas over its entire range. The small AOO certainly reflects collecting and georeferencing deficit. Discussion. Solanum aloysiifolium is widely distributed and a common plant of disturbed areas in northern Argentina. It often forms large stands and can range from tiny shrubs to almost tree-like forms. Like many species of morelloids (e.g., S. nigrum, see Särkinen et al. 2018) fruit colour is polymorphic with plants having either green or purple berries at maturity. The long-pedunculate forked inflorescences with narrowly elliptic buds that develop into deeply stellate corollas with a greenish yellow central star of shiny tissue make this species distinctive. Barboza et al. (2013) placed S. cochabambense in synonymy with S. aloysiifolium, but further study throughout the range of S. cochabambense confirmed the distinctness of the two taxa. Individual specimens collected in sympatry can be difficult to identify. Solanum cochabambense differs from S. aloysiifolium in its more highly branched inflorescences (those of S. aloysiifolium are usually only forked), buds that are ellipsoid with long-triangular calyx lobes rather than narrowly ellipsoid with short-triangular calyx lobes and larger less deeply stellate corollas. The anthers of S. aloysiifolium are narrow relative to their length (3.9-5 mm long and 0.6-1 mm wide in S. aloysiifolium versus 3.5-4 mm long and 0.9-1.2 mm wide in S. cochabambense) but this character can be difficult to see in the absence of comparative material. The berries of S. cochabambense are larger (1-1.2 cm in diameter) than those of S. aloysiifolium (0.5-0.6 cm in diameter), with similar numbers of stone cells. Leaf margins in S. aloysiifolium are usually entire, but very occasionally some plants (e.g., Nee 31497) have leaves with irregularly toothed margins, especially towards the base. Leaves of S. aloysiifolium are usually narrower than those of S. cochabambense where they grow in sympatry, but this is not a consistently reliable character. Solanum aloysiifolium could also be confused with the widespread and weedy S. chenopodioides; both taxa have matte berries and deeply stellate corollas. They differ in inflorescence morphology (forked in S. aloysiifolium, unbranched in S. chenopodioides) and stone cell number (ca. 10 or more in S. aloysiifolium, absent in S. chenopodioides). The distinctive down-turned fruiting peduncle of S. chenopodioides is never found in S. aloysiifolium.Published as part of Knapp, Sandra, Saerkinen, Tiina & Barboza, Gloria E., 2023, A revision of the South American species of the Morelloid clade (Solanum L., Solanaceae), pp. 1-342 in PhytoKeys 231 on page 1, DOI: 10.3897/phytokeys.231.10089